wrapped FlannBasedMatcher (and extended DescriptorMatcher wrapper)

updated feature_homography.py sample to use new features

modules/features2d/include/opencv2/features2d/features2d.hpp

@@ -2237,24 +2237,24 @@ public:
      * Add descriptors to train descriptor collection.
      * descriptors      Descriptors to add. Each descriptors[i] is a descriptors set from one image.
      */
-    virtual void add( const vector<Mat>& descriptors );
+    CV_WRAP virtual void add( const vector<Mat>& descriptors );
     /*
      * Get train descriptors collection.
      */
-    const vector<Mat>& getTrainDescriptors() const;
+    CV_WRAP const vector<Mat>& getTrainDescriptors() const;
     /*
      * Clear train descriptors collection.
      */
-    virtual void clear();
+    CV_WRAP virtual void clear();
 
     /*
      * Return true if there are not train descriptors in collection.
      */
-    virtual bool empty() const;
+    CV_WRAP virtual bool empty() const;
     /*
      * Return true if the matcher supports mask in match methods.
      */
-    virtual bool isMaskSupported() const = 0;
+    CV_WRAP virtual bool isMaskSupported() const = 0;
 
     /*
      * Train matcher (e.g. train flann index).
@@ -2267,7 +2267,7 @@ public:
      * if it has not trained yet or if new descriptors have been added to the train
      * collection).
      */
-    virtual void train();
+    CV_WRAP virtual void train();
     /*
      * Group of methods to match descriptors from image pair.
      * Method train() is run in this methods.
@@ -2291,9 +2291,9 @@ public:
      * Group of methods to match descriptors from one image to image set.
      * See description of similar methods for matching image pair above.
      */
-    void match( const Mat& queryDescriptors, vector<DMatch>& matches,
+    CV_WRAP void match( const Mat& queryDescriptors, CV_OUT vector<DMatch>& matches,
                 const vector<Mat>& masks=vector<Mat>() );
-    void knnMatch( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, int k,
+    CV_WRAP void knnMatch( const Mat& queryDescriptors, CV_OUT vector<vector<DMatch> >& matches, int k,
            const vector<Mat>& masks=vector<Mat>(), bool compactResult=false );
     void radiusMatch( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, float maxDistance,
                    const vector<Mat>& masks=vector<Mat>(), bool compactResult=false );
@@ -2562,10 +2562,10 @@ void BruteForceMatcher<L2<float> >::radiusMatchImpl( const Mat& queryDescriptors
 /*
  * Flann based matcher
  */
-class CV_EXPORTS FlannBasedMatcher : public DescriptorMatcher
+class CV_EXPORTS_W FlannBasedMatcher : public DescriptorMatcher
 {
 public:
-    FlannBasedMatcher( const Ptr<flann::IndexParams>& indexParams=new flann::KDTreeIndexParams(),
+    CV_WRAP FlannBasedMatcher( const Ptr<flann::IndexParams>& indexParams=new flann::KDTreeIndexParams(),
                        const Ptr<flann::SearchParams>& searchParams=new flann::SearchParams() );
 
     virtual void add( const vector<Mat>& descriptors );

modules/python/src2/cv2.cpp

@@ -74,6 +74,11 @@ typedef Ptr<FeatureDetector> Ptr_FeatureDetector;
 typedef Ptr<DescriptorExtractor> Ptr_DescriptorExtractor;
 typedef Ptr<DescriptorMatcher> Ptr_DescriptorMatcher;
 
+typedef cvflann::flann_distance_t cvflann_flann_distance_t;
+typedef cvflann::flann_algorithm_t cvflann_flann_algorithm_t;
+typedef Ptr<flann::IndexParams> Ptr_flann_IndexParams;
+typedef Ptr<flann::SearchParams> Ptr_flann_SearchParams;
+
 static PyObject* failmsgp(const char *fmt, ...)
 {
   char str[1000];
@@ -820,6 +825,14 @@ static bool pyopencv_to(PyObject *o, cv::flann::IndexParams& p, const char *name
     return ok;
 }
 
+template <class T>
+static bool pyopencv_to(PyObject *o, Ptr<T>& p, const char *name="<unknown>")
+{
+    p = new T();
+    return pyopencv_to(o, *p, name);
+}
+
+
 static bool pyopencv_to(PyObject *o, cvflann::flann_distance_t& dist, const char *name="<unknown>")
 {
     int d = (int)dist;

modules/python/src2/hdr_parser.py

@@ -191,7 +191,7 @@ class CppHeaderParser(object):
         if add_star:
             arg_type += "*"
 
-        arg_type = self.batch_replace(arg_type, [("std::", ""), ("cv::", "")])
+        arg_type = self.batch_replace(arg_type, [("std::", ""), ("cv::", ""), ("::", "_")])
 
         return arg_type, arg_name, modlist, argno
 

samples/python2/feature_homography.py

@@ -4,35 +4,53 @@ Feature homography
 
 Example of using features2d framework for interactive video homography matching.
 
+Usage
+-----
+feature_homography.py [<video source>]
+
 Keys
 ----
 SPACE - set reference frame
 ESC   - exit
 '''
 
+
 import numpy as np
 import cv2
 import video
-from common import draw_str
+from common import draw_str, clock
+import sys
+
+
+detector = cv2.FastFeatureDetector(16, True)
+detector = cv2.GridAdaptedFeatureDetector(detector)
+extractor = cv2.DescriptorExtractor_create('ORB')
+
+FLANN_INDEX_KDTREE = 1
+FLANN_INDEX_LSH    = 6
+flann_params= dict(algorithm = FLANN_INDEX_LSH,
+                   table_number = 6, # 12
+                   key_size = 12,     # 20
+                   multi_probe_level = 1) #2
+matcher = cv2.FlannBasedMatcher(flann_params, {})  # bug : need to pass empty dict (#1329)
+
+green, red = (0, 255, 0), (0, 0, 255)
+
 
 if __name__ == '__main__':
-
     print __doc__
 
-    detector = cv2.FeatureDetector_create('ORB')
+    try: src = sys.argv[1]
-    extractor = cv2.DescriptorExtractor_create('ORB')
+    except: src = 0
-    matcher = cv2.DescriptorMatcher_create('BruteForce-Hamming') # 'BruteForce-Hamming' # FlannBased
+    cap = video.create_capture(src)
 
-    ref_desc = None
     ref_kp = None
 
-    green, red = (0, 255, 0), (0, 0, 255)
-
-    cap = video.create_capture(0)
     while True:
         ret, img = cap.read()
         vis = img.copy()
         kp = detector.detect(img)
+        kp, desc = extractor.compute(img, kp)
 
         for p in kp:
             x, y = np.int32(p.pt)
@@ -40,14 +58,17 @@ if __name__ == '__main__':
             cv2.circle(vis, (x, y), r, (0, 255, 0))
         draw_str(vis, (20, 20), 'feature_n: %d' % len(kp))
         
-        desc = extractor.compute(img, kp)
+        if ref_kp is not None:
-        if ref_desc is not None:
+            raw_matches = matcher.knnMatch(desc, 2)
-            raw_matches = matcher.knnMatch(desc, ref_desc, 2)
+            matches = []
-            eps = 1e-5
+            for m in raw_matches:
-            matches = [(m1.trainIdx, m1.queryIdx) for m1, m2 in raw_matches if (m1.distance+eps) / (m2.distance+eps) < 0.7]
+                if len(m) == 2:
+                    m1, m2 = m
+                    if m1.distance < m2.distance * 0.7:
+                        matches.append((m1.trainIdx, m1.queryIdx))
             match_n = len(matches)
 
-            inliner_n = 0
+            inlier_n = 0
             if match_n > 10:
                 p0 = np.float32( [ref_kp[i].pt for i, j in matches] )
                 p1 = np.float32( [kp[j].pt for i, j in matches] )
@@ -66,7 +87,8 @@ if __name__ == '__main__':
         cv2.imshow('img', vis)
         ch = cv2.waitKey(1)
         if ch == ord(' '):
-            ref_desc = desc
+            matcher.clear()
+            matcher.add([desc])
             ref_kp = kp
             ref_img = img.copy()
         if ch == 27: